Operators

Overview

An Operator is a method of packaging, deploying and managing a Kubernetes application. A Kubernetes application is an application that is both deployed on Kubernetes and managed using the Kubernetes APIs and kubectl tooling.

To be able to make the most of Kubernetes, you need a set of cohesive APIs to extend in order to service and manage your applications that run on Kubernetes. You can think of Operators as the runtime that manages this type of application on
Kubernetes.

The Operator Framework

The Operator Framework is an open source project that provides developer and runtime Kubernetes tools, enabling you to accelerate the development of an Operator. The Operator Framework includes:

Enables developers to build Operators based on their expertise without requiring knowledge of Kubernetes API complexities.

Oversees installation, updates, and management of the lifecycle of all of the Operators (and their associated services) running across a Kubernetes cluster.

Build with the Operator SDK

The SDK provides the tools to build, test and package Operators. Initially, the SDK facilitates the marriage of an application’s business logic (for example, how to scale, upgrade, or backup) with the Kubernetes API to execute those operations.
Over time, the SDK can allow engineers to make applications smarter and have the user experience of cloud services. Leading practices and code patterns that are shared across Operators are included in the SDK to help prevent reinventing the
wheel.

Lifecycle of an Operator

Once built, Operators need to be deployed on a Kubernetes cluster. The Operator Lifecycle Manager is the backplane that facilitates management of Operators on a Kubernetes cluster. With it, administrators can control what Operators are available
in what namespaces and who can interact with running Operators. They can also manage the overall lifecycle of Operators and their resources, such as triggering updates to both an Operator and its resources.

Operator FAQ

Operators are purpose-built to run a Kubernetes application, with operational knowledge baked in. They will be smarter and more tailored than generic tools.

The cloud-like capabilities that are encoded into the Operator code can provide an advanced user experience, automating such features as updates, backups and scaling. All of this is accomplished using standard Kubernetes tools, CLI and API.

What are benefits of using the Operator Framework?

If you are a community member, builder, consumer of applications, or a user of Kubernetes overall, the Operator Framework offers a number of benefits. Operators are built on top of a common set of Kubernetes APIs. They act like cloud services,
make it more simple to install and update Kubernetes applications, without having to worry about the underlying platform.

Operators helps your teams to build a great automation experience. They allow teams to build in expertise of automated operations, instead of building manually each time.

How does the Operator Framework make hybrid cloud easier?

For consumers of applications across the hybrid cloud, keeping those applications up to date as new versions become available is of supreme importance, both for security reasons and for managing the applications’ lifecycles and other needs.
The Operator Framework helps address these user requirements, aiding in the creation of cloud-native applications that are easier to consume, to keep updated, and to secure.

Who builds an Operator?

Operators are best built by those that are experts in the “business logic” of installing, running and upgrading an application.

Experience has shown that the creation of an Operator typically starts by automating an application’s installation and self-service provisioning capabilities, and then evolves to take on more complex automation.

Who deploys an Operator?

Operators are deployed by end-users through the Lifecycle Manager. Common patterns are for centralized infrastructure teams to grant access to a team’s Namespaces to run specific Operators. Afterwards, each team can manage, upgrade and scale
their Operators in a self-service manner.

Operators can package internal applications at an enterprise, software that is deployed by commercial customers, or popular open source projects. Operators can even power a SaaS environment with a large amount of individual instances of an application.

Does an Operator require Kubernetes?

Yes, Kubernetes is required, but range of versions/distros are supported. The goal is to provide tooling to build Kubernetes applications, Operators, that are independent to a specific vendor or cloud platform.

Do I always need to write my own Operator to get value out of the Operator Framework?

You do not need to write your own Operator in order to get value out of the Operator Framework. Operators can be written such that they can be reused for applications. This means that you can, for example, create a generic Helm Operator that can be specialized for individual Charts. Even applications that do not require more than the built-in Kubernetes Workloads APIs can benefit from the lifecycle management and unified user-experience provided by the Operator Framework.

The Vault Operator makes it easier to install, manage, and maintain instances of Vault – a tool designed for storing, managing, and controlling access to secrets, such as tokens, passwords, certificates, and API keys – on Kubernetes clusters.